Ultrafast charging lithium-ion batteries have huge potential market size on demand due to their shortened charging time which can be as quickly as refueling for gas-powered vehicles. However, high-rate recharge produces sudden heating, which gives rise to a fire hazard for high-power batteries with high-cost metallic lithium anode as well as new high-capacity anode materials, such as micro/nano silicon1, SnO22,3, or Co3O44. Compared with the progress of the high-performance cathode materials5-8, there is an urgent task to develop high-performance anode materials for safe high-power lithium ion batteries. Spinel Li4Ti5O12 (LTO) is an ideal host owing not only to its ‘zero-strain insertion’ structural characteristics, but also to its low cost, abundance and environmental benignity.9 However, the inherent insulating characteristic of LTO seriously limits its high-rate capability, which is a key parameter to obtaining high-power density in batteries.10 
In principle, the charging-rate capability of safe lithium ion batteries depends largely on the performance of anode for lithium storage. Although the addition of conductive additives could improve its surface electronic conductivity for achieving high rate capability15, the cost of LTO materials is increased due to complicated procedures and some expensive additives. On the other hand, LTO materials obtained by molten-salt method often need to undergo long-time and high-strength milling.16 The low surface area of sintered grains is also a crucial factor that hampers the improvement of rate performance and available capacities for LTO electrodes. Therefore, there still remains a challenging issue in developing novel structured LTO materials as suitable anodes for ultra-fast charging lithium ion batteries.
To solve the above problems, nanostructured electrode materials with a larger surface area and short path for lithium-ion migration were exploited for increasing the active material/electrolyte interface and shortening the time of Li-ion insertion/extraction. It has been demonstrated that nanostructured LTO materials, such as nanocrystals,17 nanowires,18 hierarchical structure19 as well as their composite with conductive additives,20 could help to fulfill such purpose and also facilitate the electrochemical insertion/extraction of lithium ions. However, although the addition of conductive additives could improve the high rate capability of LTO15-18, the cost of LTO materials is increased due to complicated procedures and some expensive additives.
Furthermore, although ultrathin nanosheets are a desired framework for lithium storage owing to large exposed area and short path for Li ion transfer, smooth facets of the nanosheets are easily bonded when overlapping with each other at high temperatures, which leads to a decrease of surface area and affect the battery's performance. Although assembling the nanosheets into the hierarchical structure is an efficient way to increase their surface area, the high porosity of the electrode makes the power density low and the reported surface area of LTO or TiO2 nanosheets is no more than 140 m2 g−1.21 